Within the one boson exchange model, $Delta$-mass dependent M-matrix and its influence on the calculation of $NDelta to NN$ cross sections are investigated. Our calculations show that the $m_{Delta}$ dependence of $|textbf{p}_{NDelta}|$ and $|mathcal{M}|^2$ has effects on the calculations of $sigma_{NDeltato NN}$, especially around the threshold energy. We finally provide a table of accurate $sigma_{NDeltato NN}$ which can be used in the transport models.